This works: on arrival after the qualifying segment call the airline and ask them to annotate the PNR to reflect the fact you have attained such and such status. On entry to a lounge ask the agent to please read your PNR.

That's it; you don't have to wait for the card, or the miles to be credited, or for your new status to show on your profile. A correctly worded annotation on your PNR is all that it takes,