tex-mode-hook not working anymore?

[Fabrice Delente <delentef@gmail.com>]

Hello.

This is with GNU Emacs 24.2.1.

I have set tex-mode-hook to add keyboard shortcuts to custom elisp
functions in my .emacs:

(add-hook 'tex-mode-hook
          '(lambda ()
             (define-key tex-mode-map [?\C-,] 'insere-une-virgule)
             (define-key tex-mode-map [?\M-\(] 'comment-region)
...etc.
))


However, it stopped working today. When I hit one of my shortcuts, I
get "undefined" in the minibuffer.

How can I restore it?

Thanks.

--
F. Delente