Virtualenv's pylint not found

When I set up my virtual environment in emacs, I also configure flycheck's pylint to point to the executable that's in the virtual environment. The way I'm doing this right now is:

    (defun my-set-pylint-from-venv ()
      "Change flycheck pylint executable to virtualenv executable"
      (if (and (boundp 'virtualenv-name)
               (virtualenv-p (py--normalize-directory virtualenv-name)))
          (let ((pylintpath
                 (concat (py--normalize-directory virtualenv-name) "bin/pylint")

                 ))
            (setq flycheck-python-pylint-executable pylintpath)
            )))
    (add-hook 'python-mode-hook 'my-set-pylint-from-venv)

but this means if I open a Python file, then go "oh yeah, I need to set the virtual environment" and set it with (virtualenv-workon), then I also need to do (python-mode) again in order to hit the pylint executable hook.

The way I'd rather do this is make it a hook to (virtualenv-activate) or (virtualenv-workon) so I can stop restarting python-mode every time I switch venvs.

Is there a way to automate this that actually supports the workflow I've described?