Over the history of the National Hockey League there have been three instances in which the league had an odd number of teams.
The first was in 1978 when the league contracted one franchise by merging the Cleveland Barons with the Minnesota North Stars. This left the league with a total of 17 teams. This would last just one season.
The very next year, the NHL essentially bought out the World Hockey Association. In doing so, three Canadian Teams (Oilers, Jets, Nordiques) and the Hartford Whalers (sorry Canada) were added to the NHL for a total of 21 teams. The NHL would hold firm with the odd number of teams for the next 21 years.
Finally, in 1997 the NHL announced the awarding of four NHL franchises which would bring the league from 26 to 30 teams. However, because only Nashville was ready to go the following year, the league played with 27 for one season.
So what did we learn? It is absolutely possible that the league chooses to expand to Las Vegas without awarding a franchise to Quebec (or Seattle or anyone else) However, based on the history of the league, they would certainly rather have an even number of teams. The Original Six expanded to 12, then 14, then 16 then 18. The modern NHL had 22, then 24, then 26, then essentially 30 (see above).
So, though it is possible, it’s not terribly likely that they decide to expand to Vegas without a partner.
In other words, we aren’t completely tied to Quebec, but there’s no doubt the path of least resistance is for Vegas and Quebec to come in together in 2017-18.