Inactive Tutor answered 04/13/19
Tutor
New to Wyzant
My guess is simply that the pronunciation "À l'une" would be confusing. It could be interpreted as "à Lune", where "Lune" is the name of a commune or village, on a par with the villages of "Lunel" (in the département of Hérault) and "Lunéville" (département of Meurthe-et-Moselle).