I use Adloquium quite a lot personally. It is usually a good idea to use it when the tank is getting damaged constantly and falls below 50%. You hit him/her with an Adloquium, and you should have enough time to throw in a Physick or two without him/her dropping any further, or even heal someone else.
It can be used in conjunction with other spells as well, such as after a Lustrate.
There are many other situations where Adloquium is very useful, so give it a try, but also don't spam it.

It is also a matter of play style; other fellow healers play Scholar differently, using less Adloquium and more Physick, etc.