A cell array is the wrong way to store these data. You want a table, or probably a timetable. The fact that you say, "the name of the variable is EventLTEEvents" makes me wonder if you already have that. And I recommend that you store text in those tables as string, not as cell arrays of char rows.
Once you have that, deleting rows based on a condition is just subscripting, e.g.
T(T.X > 10,:) = 
In your case, the condition is probably something like strlength(T.EventLTEEvents) > 0.