How to get month names starting with a capital in Format->Cell

In French, month names don’t start with a capital UNLESS they are the first word in the sencence.

For example:

Nous sommes le lundi 15 janvier 2014.

Janvier est le premier mois de l’année.

In Calc, when I click Format → Cell → Number, and select MMMM as th format for a date, the output is janvier, without a capital letter. Since that is the only word in the cell, it makes sense to have it start with a capital letter.

What should I do in Format → Cell → Number to get Janvier instead of janvier?

I see no way to do it with number formatting. Do you need it as number? If it is a text, you can use the function PROPER to capitalize the string. For example, if A1 contains the date, then =PROPER(TEXT(A1;“MMMM”)) would result the string Janvier.

I have tried to define a sorting list too, which has capitalized month names. But that does only work for direct text entries.