"It must have been a lucky coincidence, then," she said.

Still, it could have been simply a lucky coincidence.

Everyone has been exclaiming about what a lucky coincidence it is that Elinor's over here, so the two families will be able to meet.

The visit to the Peregrine turned out to be a lucky coincidence.

The first was a lucky coincidence, the other times he went to the city where she would be, creating business to take him there.

Our meeting at the Memorial was a lucky coincidence.

Seemed like quite the lucky coincidence, if you asked me.

Or is this just a lucky coincidence that we've bumped into each other again so soon?

In several instances, it worked, though it was likely only a lucky coincidence.

Her visit was a lucky coincidence, since it distracted your mind from the real object of my questions.