After remaining in Acheen about eighteen months, Lockhart returned to India, where he joined the Quartermaster-General's Department, and at the beginning of the Afghan War he was chosen to take charge of the line of communications up the Khyber. He afterwards joined Lord Roberts' Staff as Assistant Quartermaster-General at Kabul, and for a short time acted as Chief of the Staff on Charles MacGregor being selected for the command of a brigade. In that capacity he had hoped to accompany his illustrious Chief in the march from Kabul to Kandahar, but General Chapman being his senior on the staff, it was decided, much to Lockhart's disappointment, that he should return to India as Chief of the Staff with the troops under Sir Donald Stewart's command. He received a C.B. and brevet Colonelcy for his services in Afghanistan, and was afterwards appointed Deputy Quartermaster-General for Intelligence at Army Headquarters, where he remained until 1886, when Lord Roberts became Commander-in-Chief in India in succession to Sir Donald Stewart. He was then sent on an exploring expedition with the late Colonel Woodthorpe, R.E., to Chitral and Kafiristan, and the admirable report which he drew up was of the greatest value to the Government of India in considering what steps should be taken to guard the northern passes between the Pamirs and the Peshawar Valley. On his return to India, Lockhart was offered the Quartermaster-Generalship in that country, but he preferred the command of a Brigade in Burma, where he greatly distinguished himself by his activity in pursuit of Dacoits. His health, however, was undermined by continual attacks of fever, and he had to be invalided home, where, after a short interval, he became Assistant Military Secretary for India at the Horse Guards. After holding this post for a couple of years, he accepted the command of the Punjab Frontier Force, which was offered him by Lord Roberts, and in that capacity he commanded a brigade in the Black Mountain Expedition under the late Sir W. K. Elles, and held the chief command in the Waziristan and Isazai Expeditions. No abler or more sympathetic general ever commanded the Punjab Frontier Force; he was beloved alike by the British officers and the Native ranks; he maintained the traditions of the Force and raised it to the highest standard of efficiency; and when he left it he had good reason for regarding it, as he always did regard it, as the _corps d'elite_ of the Indian Army.