When I was prescribed Lexapro, my doctor said that it affects individuals differently.
For some, it wakes them up so they are advised to take it in the morning.
For others, it makes them tired, so they are advised to take it at bedtime.
So, see how it goes for you and how it makes you feel, then take it at the same time each day at whatever time works best for you.
Did your prescriber advise you on the time of day to take it?