It occurs to me that Ludovicus, the Latin form of Lewis and perhaps Louis in
French are the same name. Pronounciation centuries ago often meant that the
final letters, such as "s" and "x" were pronounced as in Norman
Louis would have been pronounced like Lewis. I have been told that in one of
my family's surnames, Devereux, the "x" was always pronounced i.e.
"Deverooks". In modern times the last letters in both Louis and Devereux are
no longer sounded.