imo elegance are the trickiest lps to keep, its by far my favorite coral but its very fragile.
they love the light but its possible to burn them up their flesh is very delicate and they do not heal well unless your tank is VERY healthy.
elegance do not tend to do so well in new tanks or ulns systems, they need "dirtier" water.
having strong flow isnt ideal as well, plus elegance love to be fed.
unfortunately yours does not look like its going to make it, if it has been like that for a while it is prob slowly dieing.
its not uncommon for them to close up but they shoud not stay like this for more than a day or a half day.
if i were you i would move the elegance to a different spot and see how it reacts, and at the first sign of tentacles i would try feeding it(only once its open dont force feed it)
elegance also need to be in the sand bed, as they grow if they are on rocks their flesh will rub against rocks and then they can melt away(they do not take damage well)
my elegance is around 14" long and has about 10-15 mouths, i feed it once a day a hefty feeding of meaty foods, im only running halides but its on my sandbed directly under the 250w halides.mine doubles in size at peak lighting
good luck and cheers with this beautiful and tricky coral