An experienced pilot when the war began, Lenoir transferred to the French Air Service at the end of 1914. On two occasions in 1916, he was wounded in action while serving as a pursuit pilot with N23. While on an artillery support mission, he was killed in action when his SPAD S.VII was shot down.

Médaille Militaire
"Marechal-des-Logis pilot of Escadrille N23. Non-commissioned officer always demonstrating the best fighting spirit during the course of his numerous combats, more often behind enemy lines than behind our own. In all his actions he showed contempt for death. On 15 March 1916, while protecting a long distance reconnaissance and having his machine gun jam during the course of a combat, he completed his mission and managed to ward off enemy planes by a series of audacious maneuvers. He returned with his plane riddled by bullets." Médaille Militaire citation, March 15, 1916

Chevalier de la Légion d'Honneur
"Adjudant pilot of Escadrille N23. Pursuit pilot beyond compare, setting the highest example of energy and self-sacrifice. During eleven months of uninterrupted service in his Escadrille, he has had 91 successful combats, returning frequently with his plane riddled by bullets. He shot down his sixth enemy plane on August 4, 1916." Chevalier de la Légion d'Honneur citation, August 9, 1916