i am not sure if elements has the rotating crop, try opening your pic,select crop tool then just put a small long crop along the horizon,
when you move your cursor near the corner (not on the corner,just outside the crop) it should change, if you left click and hold you can now rotate the crop up or down.
at any time you can let go of the corner ,go to middle of top line and drag the crop up or down over the horizon to check that its level, if its not then rotate the crop a little more from the corner.
once you have the horizon level you can expand each bit of the crop by dragging to suit.
finally double click the inside of the crop to finish .
i am not very good at explaining so i hope this makes sense. cheers nomad