Frances's blog...

...not  Frances'  blog. I am not the pleural of France, therefore why am I not allowed that extra s that is given to other people's possessives?

This is a common misuse. It appears regularly in published books and newspapers. Any noun that ends in an s - personal or not - is refused that extra s for its possessive (Jesus', Mavis', Boris'  etc etc).

This has been bugging me for some time, and now I've finally got it off my chest. Phew!

(My iPad refuses to use my name at all, and calls me France's unless I manage to stop it in time.)