I followed her suggestion of using hot glue to affix a foam brick to the bottom and then covered it with spanish moss and a mixture of several other mosses that I had on hand. I chose the same pinkish-purple orchids from Hobby Lobby and stuck them in.
I added an abandoned bird's nest from the yard...
and the stems were a little flimsy so I used a wooden skewer tied with a piece of raffia to support them.
Using sales and coupons the total for the flowers and leaves came in at around $20 (I already had the moss and shell). Not bad considering the cost of one real orchid, and I think this faux arrangement is quite convincing.
If you're looking for an idea for a Spring arrangement, something like this would be pretty in any vessel... a vintage trophy cup or ice bucket, an old dough bowl, a pewter serving piece, a classic piece of blue and white pottery, a pretty piece of milk glass, or even an interesting basket.