Well I did think it was asinine of Cruz to make his acceptance of Trump’s gracious offer all about the absence of endorsement talk. But as you said, we’ll see.
Your link just showed us that Cruz's response wasn't "all about" the absence of an endorsement.
Cruz said. “Our country is facing enormous challenges and I do not believe it is the responsible choice for conservatives to shy away from defending the principles we believe in, from talking about who America is and how we go forward to get on a better path, and that’s what I intend to do at the convention.”
And a well timed endorsement at the convention would certainly preclude an endorsement, when asked about it before the convention.