This is a bit convoluted, but it works.

1) Click on the WorkArt icon

2) Select the bowed up WordArt type, (not critical, but you'll need to
select something)

3) In the text section, add the top half of the text, then two (2) returns,
then the bottom half of the text.  You will get something ugly on the slide,
don't worry.

4) Select the ugly WordArt.

5) You should get a WordArt Toolbar that pops up, if you do not, right click
the WordArt and select "Show WordArt Toolbar"

6) Select the icon on the pop-up toolbar that looks like a distorted A (not
the first one that is merely crooked).  If you hover the pointer over it for
a minute it may show the tooltip 'WordArt Shape'.

7) Second row, fourth icon over is a shape called Bottom (Curve) that looks
like a closed lowercase e.  Select it.

8) Re-size the WordArt to fit.