Hi Lisajane,
Welcome to
RP!
On the same site your example picture is, I found this very nice
Tutorial on how to achieve a High key effect on black&white images with Photoshop .... If you scroll down the page you'll find "
Technique Two: Katie Arndt’s Technique" which is the one I follow with my picture (please, keep in mind that my picture is a far cry from the quality and resolution of the image used for the tutorial!!!

)
Putting back some colour in your High Key image...
Following the Tutorial, at a certain point, you are asked to "
Duplicate the Background Image, set the Blending Mode to Overlay and apply Gaussian Blur to taste."
When I was happy with the B&W result, I merged visible keeping all the underlying correction Layers (the action for merging 'visible' without losing the underlying 'steps' can be downloaded
here.) I went back to the blurred background duplicate and, keeping its blending at 'Overlay' I just 'dragged it on top of all other layers .... Adjust its Opacity ... and that's all...
Hope this helps....