Concave lofting between plane and offset spline

[bontempiluca]

I am trying to create an organic shape to convert to a wall art like the one in this picture: 

My idea was to loft between a plane and a spline to create a shape that has the plane as the base edge and a curved spline as the top edge. The issue that I am facing is that the lofting returns an error due to self-intersections and I am not sure how to work around that. There is probably a better/easier way to obtain that result. 

Below a screenshot of the geometry that I obtain using the loft function between one edge and the sp...

[TrippyLighting]

Please share your model.

I personally would not use lofts but T-Splines to model this.

[bontempiluca]

Thanks for your answer, I managed to make some progress as you can see from the model attached, but it is still not exactly what I was hoping for. 

Could you break down the steps that you would use to model something similar to the original example using T-Splines?

I am still finding my way around the tool, so any detail would be much appreciated 🙂