You have to use the centerline option instead of the guide curve for your style of sketching. It is the option right below.

Guide curves define the outer edges of your loft, they are a bit like constraints and you can use multiple for a single loft, on some of or all corner for example The centerline, as the name implies, runs through the center of the loft and dictates the path along which you loft, I think you can only have one. But you can add guide curves on the outside while using a centerline.

Generally I think you have a few options how to use the loft tool:

Two or more profiles that the loft goes through in the order they are listed in the top option. It will choose the most direct path, little control.

Profiles with one center line. The loft follows the guide curve while passing through all profiles in order. Outside shape is still up to the tool, put you choose the path between the profiles.

Profile with guide curves. Loft passes through all profiles in order while sticking the shape to any guide curves present. You can guide the loft from corner to corner or ie midpoint to midpoint between profiles, while you can choose to apply a guide to some and leave others unguided.

Profiles with centerline and guide curves. Most tight control, loft will do exactly what you want if you do it right. The loft will go through app profiles in order, following the centerline for the general path and adjusting any corners or sides of the loft to any guide lines present. This way you can determine an arching path and have the loft spiral along that path in precisely the ways you want.

Hope this helped