Hello! I'm curious about the greeting to give in relatively formal emails in French, such as to a professor or other professional. In English, we start with "Hello (Name)", "Hi (Name)", or just "(Name)" on the top line, then typically add a few lines and write our message. In French, I've only seen "Salut (Name)" as the first line. Could someone use "Bonjour..." here also, or would it be inappropriate because emails are not restricted to simply the day? (Hence "good day" wouldn't work.) On the other hand, if that was acceptable, if it was nighttime while you were writing the email, could you write "Bonsoir"? Merci d'advance!