Whoever or Whomever?

[BoneMan]

Microsoft Word 2008 recently gave me the dreaded green squiggly for the use of “whom” in a sentence. Although I usually distrust Bill Gates in most things grammatical, I decided this time to see the explanation page for Word’s reasoning, and, to my surprise, ran across the following cited as an example:

Instead of: Tell it to whomever lost the book.

Consider: Tell it to whoever lost the book.

To me, “whoever” looks like the object of the preposition “to” in that sentence, and so it should be “whomever”.

A Google search turned up convincing arguments for both sides, so I am torn over which case is correct.

Would anyone care to settle the matter for me?

[Chief_Pedant]

@BoneMan

Microsoft Word 2008 recently gave me the dreaded green squiggly for the use of “whom” in a sentence. Although I usually distrust Bill Gates in most things grammatical, I decided this time to see the explanation page for Word’s reasoning, and, to my surprise, ran across the following cited as an example:

To me, “whoever” looks like the object of the preposition “to” in that sentence, and so it should be “whomever”.

A Google search turned up convincing arguments for both sides, so I am torn over which case is correct.

Would anyone care to settle the matter for me?

In this case, whoever.
You can always use me as the cite, but if you want another:

Whoever vs. Whomever | Grammar Rules