Like many have said on here, this is (probably) very much a long shot, but I remember that I really enjoyed a certain young adult mystery novel when I was a little girl that I've been wondering about for years.

I'm pretty sure it was published around the 70s (though it could have been the 80s, but it seemed quite old). The plot was based around a family of children and their mother (from what I hazily recall, their father was absent for some reason) who were tormented by the peculiar antics of a poltergeist, such as things being overturned and stones being thrown seemingly from nowhere in their sun room. I believe a statue of some sort was involved as well. The word "cupid" was either in the title or somehow majorly relevant to the plot.

Any ideas?