Cats begin urinating where they shouldn't to get your attention. There is a reason behind this bizarre behavior. It may be a urinary tract infection, a bladder infection, or some of the other reasons mentioned above, like a turf war. Or the box may not be clean enough. Or the litter may be bothering her; if you have switched brands, that even could cause it. The only time my boys have ever peed where they shouldn't, they were trying to tell me something: Hunter has done it twice and it was a UTI both times. I would recommend having Arwen checked.