Bah, humbug. The sentence is fine, rule aside, parsing aside. The sentence is isolated, out of context, but with any degree of thought at all it is clear that the referent is "Toni Morrison." I would disagree with the rule that the referent needs to appear in each sentence. We would assume here that Toni Morrison had been named in an earlier sentence, but, even if she had not been named, even if this were the opening sentence in an essay, the meaning remains clear.

Grammar should serve the clear expression of thought and not the other way around. Again, bah, humbug.