Well, there are lists, and then there is reality.
People do tow them, so it's possible. Here's a link
to a Google search of iRV2 posts with the terms "Honda," "Element" and "toad" in them.
The best place to start is with the owner's manual for the year you are considering. It should have a section on "Recreational Towing" that says if the year and model is towable four-down, and if so, what the procedure to prepare it for towing is. Here's a link
to Honda's Web page for the manuals.
NOTE: Some folks have towed vehicles the manufacturer has said are not towable.
We own a 2003 Element AWD. We could not tow it behind our former coach, due to its weight. I seem to remember the manual OK'd four-down towing. But, don't take my word for it.