This is what I got from a literal reading of the rules and application of the various sections regarding line of sight, line of effect and reading a power...sorry for the lack of better reference, but I don't have my notes for this with me. I looked all over for a CS ruling and found a bunch, but they were contradictory on pretty much evey point.
1) The creation of the sphere and attacking with the sphere require line of effect. (the Line of Effect page in the PHB)
2) Sustaining the sphere and moving it do not require line of effect. (Nothing in the books say those actions do.)
3) Using the power to create the sphere initially and attacking with it are use of a ranged power and making a ranged attack so you take OAs. (The opportunity attack page in the PHB).
4) Sustaining the sphere and moving it do not provoke OAs. (Nothing in the book says it does.)
5) You do not need line of sight to create, attack with, move or sustain the sphere (The line of sight page in the PHB for the first two and no mention of such a requirement for sustaining or moving).
6) You attack with the sphere, so penalties for attacking with the sphere are based upon your view of the target (You need line of effect to make a ranged attack. You make another attack with the sphere as a standard action for follow up).
The wording of the power in the initial effect can be an issue (and the sphere attacks) but it doesn't specify that anything about the power changes in regard to acting as a ranged power because of that wording.