What I've been told (by folks who studied in Japan, though none were native to the language) is that Sensei is an honorific. It's apparently often used when addressing someone with specialized knowledge when you are asking them for advice/help. I may be misremembering this, but I think they told me it was even used when talking to an attorney.In University I took a intro to Japanese course and basically came to the conclusion that pretty much everything I had learnt about Japanese through non-native speakers in martial arts clubs was wrong. Ok, maybe wrong is too strong of a word, but just kind of... "off". It's been almost 20 years and I've forgotten pretty much everything, but...
Language works together as a whole, it needs context. Without that we try to take the word and give it a definition in English. But that doesn't always work, because the context is lacking and the cultural context is off.
Sensei was one of those words. It's not a title, it's not something you use towards yourself. You don't introduce yourself as "Sensei ____", it's usage had more to do with a relationship and the context. It had bugger all to do with getting a black belt.
So I'd say your question is a "no" because their is no relationship their, so the honorific "sensei" has no real meaning.
Of course at this point we have basically taken the word "Sensei" and added it to the English language giving it the meaning of "Martial arts teacher", but personally I'll stick to the words we already have in English where a good one exists. I go by "Andrew" or "Coach" with the kids.
I do know instructors who introduce themselves as "Sensei Smith", which would be odd (at best) to a native Japanese speaker. On a further note, I think the honorific is normally (in Japanese) placed after the name.