Lacebark elms naturally lose some of their bark this time of the year, so its hard to tell from your pictures if its more then normal? As far as the clusters coming off, it could be squirrels or other critters chewing the limbs off? If you can get me bigger pics of the tree as a whole to better evaluate it, I will be glad to give you more feedback. If your not seeing insect damage or yellowing of the canopy I would say its just under stress and shouldn't be terminal. Usually there is not much you can do at this point, perhaps use a soaker hose around the drip line to give it additional water or perhaps use a ross root feeder to bypass the turf root zone and water that way.

Please feel free to give me a call at the office if you have any further questions?<personal data hidden>  Steve