Connecting two paths but keeping one above the other

Hey everyone!

O wonder if any one could have an answer for this tricky issue. I have two paths, one sitting above the other. (fig1) I need to connect them to make one path but, keeping one above the other so I can apply a gradient so it looks like its going behind the path abave (fig2) any ideas? I've tried connecting paths but it simply makes one flat path, I've tried intertwine too but that dosn't either 😞

Any help greatly appreciated