[ED4] Lightning Bolt and fluff text

[ChrisDDickey]

The Lightning Bolt spell says that the spellcaster "raises his hand towards the sky".

Questions:
(1) Does this mean that the spell can only be cast under an open sky? Or can it just be assumed that the sky is somewhere up there - even when underground. The "Ride the lightning" spell specifically says it can only be cast under an open sky - this one does not.
(2) In general - how much attention should be paid to the "fluff text" of spell and talent descriptions. The lightning bolt spell mentions the sky, but should I just read the text as basically saying you need at least one arm free to cast this particular spell?
(3) Is there any way a spell that mentions a gesture could be cast with both hands tied behind the casters back? Assume it was already in an enhanced matrix so weaving the thread was not an issue.
(4) A spell that does not mention any arm gestures can be cast while bound?

[Baravakar]