It depends on the situation, but generally when I say it out loud I say "Lawl" because it's more pronounced, sort of a geeks way to express amusement/amazement.
I see "Lull" as the more generic way to pronounce the online variant -- yes, they're different to me somehow.
"El oh el" if it's in all caps or drawn out (at which point it becomes "el ohhhhhhhhhhhhhhhhhhhhhhhhhh elllllllllllllllllllllllllllllllllll"); sometimes "lawl". Srs bsns all up in here