There are two artists with this name:
1) Ronny was a french girl, who moved to The UK to become part of the Blitz Kids movement. In the early 80s she worked with artists like Rusty Egan, Midge Ure and Yukihiro Takahashi and released couple of singles. Then she disappeared from the public eye.
2) Wolfgang Roloff alias "Ronny" is a German "Schlager" singer.
1) Ronny used to be a Top French Model. She was brought up in the grim Northern industrial area of France and left home at 14 to go to Paris