1845, and was severely wounded at Sobraon.
When (Sir) Henry Montgomery Lawrence [q. v.] became resident at Lahore, Lumsden was chosen by him as one of his assistants, and was appointed on 15 April 1846. He accompanied Lawrence to Kashmir in October, and in December he was sent with three thousand Sikhs and six guns through the Hazara country. His march was opposed by some seven thousand hillmen, but by skilful stratagems he forced the passage of two tributaries of the Jhilam, near Muzaffarabad, and brought the hillmen to submit after two sharp actions. He received the thanks of the government, and was charged with the formation of the corps of guides for frontier service. He was given a free hand in the recruiting, training, and equipment of this force, which was to consist of about a hundred horse and two hundred foot. He chose men from the most warlike tribes of the border, men notorious for desperate deeds, or, as he put it, 'accustomed to look after themselves, and not easily taken aback by any sudden emergency.' The equipment of the guides included the adoption of the khaki uniform, which Lumsden was the first to introduce into the Indian army.
The guide cavalry distinguished itself under him during the siege of Multan in 1848, and again on 3 Jan. 1849, when it surprised and destroyed a raiding force of Sikhs on the Kashmir border. Lumsden again received the thanks of government. He was present at the battle of Gujrat on 21 Jan., was mentioned in despatches, and received the Punjab medal with two clasps. His corps had proved so useful that its strength was raised on 19 June to four hundred horse and six hundred foot. As assistant commissioner in Yusafzai, and for a time in charge of the Peshawar district, Lumsden was concerned in many affairs with the border tribes. Lord Dalhousie wrote : 'A braver or a better soldier never drew a sword. The governor-general places unbounded confidence in him and in the gallant body of men he commands,' and warmly praised his conduct as an administrator (20 Dec. 1851).
In November 1852 he went home on leave, after fifteen years of continuous service in India. On 1 March 1853 he was promoted captain, and on 6 Feb. 1854 he was given a brevet majority for his services in the Sikh war. He returned to India at the end of 1855, and was restored to the command of the guides. In January 1857 he was sent on a mission to Candahar, accompanied by his brother, Lieutenant (now General Sir Peter Stark) Lumsden, and Dr. Henry Walter Bellew. Persia had seized Herat, and the object of the mission was to make sure that the British subsidy to the amir was duly applied to the payment of troops for the defence of Afghanistan against Persia. It was also to advise and assist the amir so far as it could without exciting Afghan jealousy. It reached Candahar on 25 April. Its position, delicate from the first, became hazardous a month afterwards, when news arrived of the outbreak and spread of the sepoy mutiny in India. But it was important, both in the interest of the amir and for British prestige, that the mission should not be recalled during the crisis ; and while his guides were fighting brilliantly before Delhi and elsewhere, Lumsden had to remain at Candahar. It is related that at this time Lumsden and his brother one night overheard some Afghans discussing the expediency of putting them to death. He left that city on 15 May 1858, and was promoted lieutenant-colonel from that date. 'The clear sound judgment and admirable temper' which he had shown was duly acknowledged (29 Dec. 1858), and he was made a civil C.B. on 5 Dec. 1859, but this was small compensation for the opportunities he had missed.
He resumed command of the guides, and served under Brigadier (Sir) Neville Chamberlain in the operations against the Waziris in April and May 1860, for which he received the medal with clasps. An attempt on his life was made on 2 Aug. by a fanatical camp-follower, but he escaped with a severe wound in his left arm. In March 1862 he was appointed to the command of the Hyderabad contingent, with the rank of brigadier-general, and this severed his connection with the guides. He became colonel in the army on 15 June. A good service pension was given to him in 1866. He went home for six months in that year, and on 5 Sept. married Fanny, daughter of Charles John Myers of Dunningwell, Cumberland, vicar of Flintham, Nottinghamshire. Early in 1869 he gave up the command of the nizam's troops, which he had done much to improve ; and, after attending the Umballa durbar to meet the amir, Shere Ali, he left India in April.
He had been promoted major-general on 6 March 1868, and was made K.C.S.I. on 24 May 1873. The offer of further employment in India, long looked for, came too late ; and on 15 Sept. 1875 he retired from the army with the honorary rank of lieutenant-general. On his father's death in 1874 he