Common sense says you should first work with a Lender.  You want to know how much house you can buy before your Realtor starts showing you homes that you potentially cannot buy.  

But first contacting a realtor is also a good step since he/she is going to find you your Dream Home.  But as a Speaker/Educator for NC Dept of Housing I found that most Realtors didn't know about the H4P loan program and who was good at Originating them.   

For instance,  I've worked with realtors that heard about the HECM for Purchase (H4P) loan program through a lender that, in the past helped them with Conventional financing. But with the H4P the lender would take 45-60 days to close the H4P loan and the Realtor vowed to never work with the H4P program again.  To the determent of his/her homebuying clients. 

 Finally convincing the realtor that we can close the loan in 30 days I got the chance to prove myself and at the same time give the Realtor another tool in the tool belt.  We closed 3 H4P sales that summer. Sales that would have never happened without the H4P program.  

The H4P program is also better than paying Cash for a large majority of the buyers.  I've rambled to long. But, I'm available for questions. 

Best regards, David.