It made what looked like a sharp turn, yes, but it was because it went retrograde relative to STEREO B.

Go here: [link to ssd.jpl.nasa.gov]

Look at the orbital diagram at the top of the page. If you don't see it, click "show orbit diagram".

Slide the slider below the diagram all the way to the right.

Slide the slider on the right of the image a little below half way.

Slide the "ZOOM" slider to about under the "m" in word image above it.

This is about the view from STEREO B.

As you can see, Elenin does indeed appear to go retrograde from STEREO B's view.

This doesn't address if Elenin has broken up.