Dave, you seem like a well informed bloke so you might be able to help me out. If I were to refer to you post by using the word "apropos" , I've always used the construction "A propos your post...." by virtue of the French origin but usually omitting the accent over the "a". But I find I'm in a diminishing minority, outnumbered by those who insert "of" immediately after it. Why do think that might be?

Cheers, Rowan