How do I print a Thunderbird contact name and address on an postal envelope?

I want to select a Thunderbird contact and print the name and address directly on to a postal envelope for mailing.

I do not want to print a list of contacts or fiddle around with single labels. Yes, I can handwrite the details on the envelope but it is not ideal. I have tried LibreOffice>Writer>Envelope but it results in all contacts being included in the output document. Ditto for mail merge. I am running:

Lubuntu 14.04.2 LTS

LibreOffice Version: Build ID: 420m0(Build:2)

Thunderbird 31.5.0

I have already successfully registered the Thunderbird contact list as a mailing list data source in LO and looked at the mail merge facility. Am I missing something?

This should be such an obvious and simple thing. Please help.