LOOKING FOR A STORY HELP

I've not got much to go on but the story was about a girl called fleur and everyone would call her flower because they
Couldn't pronounce it and she was French. she was staying in a boarding school I believe. It was kind of a thriller I think and has a boy in it that would turn up unexpectedly, his name maybe began with a p, she was kind of scared of him a bit but they became friends in a way.
He was like emotionless and kept to himself.
This was from a few years ago there was also a scene towards the end of the book where they all went camping and he was stood outside with the rain pouring down and the school had a lot of forest around it I think someone might have died in them as well.

Very vague I know