Tom - there are several reasons why your rhododendrons are not blooming this year.  They typically set buds in the prior spring so if the buds did not develop or were frozen during a cold spell, that could be the reason.  That is also the reason pruning, if needed is done right after flowering.  Also, are your rhododendrons sited for good growth?  Most require some protections from cold winter winds and to prevent winter burn and loss of buds but need enough sun in the spring and summer for growth.  Below is an article that will provide more details on site,, soil and water needs.

https://hgic.clemson.edu/factsheet/rhododendron-2/

Reviewing your soil test results, I see that your soil looks very rich in nutrients except for Potassium which is below optimum.  The ideal times to fertilize with Nitrogen (i.e. Holly Tone) is early spring and late fall so by feeding in May and July will have encouraged more greenery.  As long as the plants look healthy, don't fertilize with Nitrogen any further until late fall.   Potassium is low so you can apply periodical applications of a Potassium fertilizer between now and fall.  Whatever Potassium fertilizer you select, you can come back to the MSU soil test site and enter the package numbers into the Fertilizer Calculator (found under Tools) and the site will calculate for you how much to apply of that product for one year and 1,000 sq. ft.  Be sure to pro-rate for a smaller area as needed.  

And, your shrubs may just need a growth year to become acclimatized to the site.  Monitor them for the remainder of the year to make sure they are getting sufficient water and the soil is draining well.  Don't prune until after bloom next year.  Apply Holly Tone in early spring.  No other soil amendments are needed since your soil is healthy.

As for lowering the pH, I am including a link below to an article that will provide the details about products that can be used. 

https://www.canr.msu.edu/uploads/files/Soil_pH_Finnerann.pdf

Hope that helps!