As long as the orbiting body is much less massive than the central body (e.g. the Moon about the Earth to a fair approximation; any planet about the sun) the size and shape of the orbit don't depend on how massive the lighter body is.
That's more or less how I'd look at it.
Note that when space vehicles take off, they start out vertically until they're out of the atmosphere; then they shift to a roughly horizontal trajectory, which is apparently a more efficient way to build up speed.
Have you considered the so-called "centrifugal force"? Technically that's a fictitious force, but we can approach the same question in terms of the real centripetal acceleration, which is the inward acceleration that must be applied to keep a body in a circular orbit. For an orbit of radius r...