The Tourist : How did Alexander Pearce know?

Elise (strange name for an English woman) did not know what Alexander looked like. She was told to chose someone, anyone, who could resemble him - as he once looked. It was an entire fluke that she chose Frank. But if Alexander did not intend to be picked, why was he on the train at all?

I think Elise picking him was just chance and not part of Pearce's plan.