
Yin Mei H. answered 06/12/20
Foreign Language Tutor specializing in French, Malay & Indonesian
Also, "sur le pont d'Avignon, l'on y danse" sounds better to the ears than "sur le pont d'Avignon, on y danse".
The French do sometimes add an "extra" letter to a word in order to make a sentence sound nicer or "smoother".