There seems to be an issue with the Picatcha add-on. Initially I thought it was SSL, but once moving all things to a pure SSL site the issue of forms not loading remained. As Gravity Forms is the only plugin, I began to disable it's add ons. Once I disabled Picatcha it worked fine.
I re-enabled Picatcha, removed the element from my forms, the forms loaded.
I created a new test form - one element, a text field, and put in Picatcha.
The result, a form that has the element, plus the heading for Picatcha but nothing else.