[Grep] how catch a single quote/ apostrophe in Grep

Hi guys,

I used a grep style in order to capitalize the first letter of every word on a paragraph (for titles) and I wonder how to correctly catch the single quote/ apostrophe in the sentence, in order not to capitalize some words.

\b(?!(d.|de|des|du|et|au|aux)\b)[\u\l]

I used the following grep, which actually works fine but I had to cheat in order to make it work.

\b(?!(d.|de|des|du|et|au|aux)\b)[\u\l]

exemple of sentence to capitalize : " Messieurs, mesdames d'Arizona, bonjour "

As you could see, I used " d. " for not Capitalizing the " d' " and not making " D' ".

Since the folowwing grep doesn't work, what should I write to excatly catch the single quote/ apostrophe, rather than cheating using the dot.

\b(?!(d'|de|des|du|et|au|aux)\b)[\u\l] -- not working. the ' isn't recognized, neither \'

Thanks for your insights