Can't run jupyter kernel from virtualenv

I'm trying to use atom-notebook on Mac OS X (10.11.4) _with jupyter installed in a virtual env_. When I open a notebook file, it renders as I would expect, but if I click the play button I see the following error:

```
atom-notebook
No running Jupyter session. Try closing and re-opening this file.
```

I've tried updating the path in settings, and running Atom from the command line with the virtualenv activated, but without success. Any suggestions as to either fixes, or where to look to debug further?

Thanks,
Rob

Atom version is 1.7.2. Python 2.7.11. Jupyter package versions:

```
jupyter==1.0.0
jupyter-client==4.2.2
jupyter-console==4.1.0
jupyter-core==4.0.6
jupyter-kernel-gateway==0.5.1
```

No source files or tests are named. Start by reproducing the failure in Atom 1.7.2 with Jupyter installed in a Python virtualenv, then trace how the play button discovers or starts the Jupyter session. Done means a notebook opened in Atom can launch its kernel from that virtualenv without the reported error.

Written by the indexing model from the issue text.