In 1910, Lahoulle enlisted for four years, attending military school at Saint Cyr. While serving with the 2eme Regiment de Dragons, he was treated for wounds received in combat on 9 August 1914, returning to his regiment in December. In April 1916, he transferred to the French Air Service, becoming an observer with N48 in May. In January 1917, he was reassigned to N23 before receiving his Pilot's Brevet in May. After additional training and transfers to two more Escadrilles, Lahoulle joined Spa57 in January 1918, scoring his first two victories in March. At the end of the month, he assumed command of Spa154 where he was credited with eight more enemy aircraft. Scoring his final victory on 15 July 1918, he was severely wounded after shooting down three observation balloons. During World War II, Lahoulle served in Africa and attained the rank of General.