It is not possible with Premiere Elements.
Why not just use the repeat button on the DVD player?
As Steve says, PrE cannot do this. You might want to look into Sony's DVD Architect, as I believe that it will allow you to do an End Action on your Timeline and point it back to itself, to get the looping without having to set that in the player. Unfortunately, I use another authoring program, so cannot verify that DVD Architect has that capability.
Thanks all. I will research.