And thanks for your patronage

The Central Ohio buro onpasses this delightful paragraph, from a correction* cataloged over at the excellent Regret The Error site:

The paper has printed an apology and has agreed to make a donation to a Christian group that helps prostitutes of which the Bishop is a patron.

I know we've already taken down the National Grammar Day decorations and dismantled the floats and all, but shouldn't that be "of whom"?

* The paper running the correction, to its credit, managed to avoid the antecedence issues: "Bishop Graham is a patron of the charity."