UPDATE: The original post was simply in error about the exact grammatical issue. For this, I apologize to everyone.

The issue is not one of sentence positioning, but of whether the pronoun is a subject of a sentence (Robert and I went to the store,), or the object of a preposition. (Between Robert and me, I am the tallest.)

I was misinformed and stand corrected. The second part of this post will remain up unchanged.

On a related note, I was asked privately which, of the following two, is correct:

  1. One of my friends is
  2. One of my friends are

#1 is correct. #2 is incorrect.

Forget about the “of my friends” part. Really, this is about two pairs of words:

  1. One is
  2. One are

“One is” is correct. “One are” is not.

One of my friends is coming over for dinner. Correct.

Five of my friends are coming over for dinner. Correct.

Pair singular with “is,” and plural with “are.”