Okay, and your picture was helpful, and the lightning does spread out, I understand what you mean, but it doesn't spread out that much. When Dooku shot lightning at Anakin it all hit him, not just some of it. When Sidious's hit Mace, Yoda and Luke every single piece hit them, not just some of it. So unless the person using the lightning somehow makes it come together so it all hits their opponent then the lightning comes together to hit the object, which can be a person or a lightsaber.
And even if it does take the Force to draw it towards your lightsaber, in the no Force scenario the Jedi or lightsaber wielding person could turn their lightsaber hortiontal to block it.
I always assumes that the lightsaber's energy just sucked the lightning into it, though. But I suppose we really don't know as no official proof has yet to be provided.