"CS Lewis was not a Catholic"
I stand corrected. I remember reading that he eventually converted at the behest of Tolkien. That doesn't appear to be correct though.
Partially right. Tolkien encouraged Lewis to convert to Christianity. He did, but did not become a Catholic as Tolkien was. He became an Anglican. (That may have been the church of his parents, I don't remember. I don't think, though, that they were particularly religious either.)