Moving a spell effect that is out of line of sight?

[Stormstrider]

If I have cast Flaming Sphere or Aggressive Thundercloud and then move it behind a wall or other sight blocking things, on my next turn, am I still able to control its movement even though I no longer have a line of sight to the sphere or cloud?

[Meirril]

That is a complicated question that isn't explicitly answered. If only line of sight is blocked, I believe everything is fine. If line of effect is blocked...

"Line of Effect
A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It’s like line of sight for ranged weapons, except that it’s not blocked by fog, darkness, and other factors that limit normal sight.

You must have a clear line of effect to any target that you cast a spell on or to any space in which you wish to create an effect. You must have a clear line of effect to the point of origin of any spell you cast."

You've basically run it into an area where it can not affect. That indicates to me that it should be treated as exceeding its maximum range and cease to exist. Though I've let that slip a lot of time with a caster tossing a Flaming Sphere in their own conjured Create Pit.