I don't like Louis, I'm afraid. I too hear 'loo' in the name.
The Louis I know goes by Lou-is, the English way, although the French pronunciation (Lou-ee) seems to be becoming more 'trendy' it appears, perhaps due to Lou-ee Walsh (whom I don't like either, I'm afraid).
Spelling it Louie would be a more helpful English spelling if you didn't like the s.