He would say that his employer prohibits personal recommendations and would be correct.

Here is what I think I can write:

Hi Steven,

I hope this email finds you well. I hate to bother you with a request, but it is something quick. Last we talked about it, you would have been willing to write a LinkedIn recommendation for me if not for company A's policy against such recommendations. I quickly found out that company A does not prohibit LinkedIn recommendations and in fact you can see quite a few on my profile LINK. But I did not want to bother you so I did not ask you even though I discovered that recommendations are allowed.

Now I AM asking. Here is why: I am now temping at company B and I have recently interviewed at company C. The hiring manager at company C used to work at company A. The position at company C is perfect to me because it is exactly up my alley: it draws on my experience working in team XYZ at A. I had a good interview. At some point the recruiter called me and said that I was so far the strongest candidate by far. They even invited me for a tech talk, and I attended, of course. But they needed to talk to another guy... then they were silent for a while, and now they are telling me that they are talking to yet another guy and will make a decision next week.

So I am definitely under consideration, but it is tough. I think it would be splendid if I could send a note to the hiring manager saying "Hi Daniel, Just briefly - here is a new recommendation from my former colleague Steven from A." And my hope is that you will do what M. (my first tech lead) did: just take the performance review that you once wrote and reformat it for LinkedIn. I was hoping that it would not take more than 15 minutes.

Thank you,
H-B.

Now Blue, here is another option. I know Steven's friend at A., Joe. I did not work with him professionally, in fact, I barely met him in person, but he helped me a great deal when he found out about my bp and suicide attempt: he recommended that I read "The Unquiet Mind" and that is how I asked for Lithium, which has been hugely helpful. And we correspond by email every once in a while. He is always very supportive and encouraging. So I can just state my situation to Joe and ask for his feedback on my letter to Steven.

Thank you!