I was advised to purchase two pounds of Organic Elemental Sulfur. Where can I purchase this?
Check several locations in my area; not available.

Not knowing where you are I'm assuming USA? Both Lowes and Home Depot say online that they have it, also the following:

https://www.planetnatural.com/...

You could also try a farm supply store if you have one nearby.

I'm assuming this amount is based on a soil test?

Where are you located? Sulfur should be available at most Nursery, Hardware, Big Box stores. Anywhere that carries lawn /garden supplies.

Welcome to NGA, @elainech !

I agree with the above, it's a pretty common item where gardening supplies are sold (assuming you are in the USA -- ?)

If you find some, there may be a helpful person that may suggest a sulphate, I would recommend you stick to the sulfur. But keep in mind, if your soil is anything like mine you will also need compost.I learned that putting just sulfur in your soil is like adding gravel, all it does is SIT THERE. The symbiotics are manifold and extensive, but organic matter and living soil is required for the sulfur to work. That and moisture.

I had hastily put in sulfur into my beds ( I have 12 with 4 more planned ) but I don't have near enough bio matter for all of them, so there are still a couple beds that are native clay soil with yellow and white freckles -I also added a bunch of perlite- and have been that way for two seasons now.