And actually the way that it works is that the ellipse that you make will actually have the ellipse axis pointing towards the direction that you click the first point in.

So when you click the first point of the elliptical arc not on a quadrant point that means that the base ellipse that you're making an arc from is a rotated ellipse.

If you want to have an arc segment from a non-rotated ellipse then you would need to draw a full ellipse and trim it to get that particular kind of elliptical arc segment.

- Michael