What site do you think you're on? The majority of the board's going to prefer it on a boy.
I think it works fine for either. If you're nickname obsessed, it works better as a girl's name. If I had to use it, I'd use it on a boy, but, as usual, most -on names are off limits for me, especially any as surnamey as this. I get called by my last name frequently even though my first name is not a surname.
Rosalie Evander Larkin
Starlight Nocturne Grey
www.behindthename.com/pnl/59411