Guided (English) tours of the Carcassonne Chateau

I exhausted my knowledge with the previous post. I've been all over the national monuments website and can't see where it says. Use this: http://carcassonne.monuments-nationaux.fr/fr/ Then click 'Coordonnees' and you'll see an email tab (it's the one with an '@' sign. Blanks are: last name, first name, email address, question, and type the characters you see. There should be an eglish button somewhere, but I never spotted it.

Yep. English and a half dozen other languages.

Can you reserve ahead? If not, what is the a.m. time, and how would one find out whether an English tour will be offered off-season? (late March)