Opportunely or opportune seasonably or seasonable
- at an opportune time
- introducing a different sort of topic
- of an appropriate or important nature
1660s, "opportunely," from French
speaking of ...
- talking of ...
- apropos [coll.]
- by the by
- dedicated to
One of his first efforts was a solid argument for freedom of discussion, in a series of letters to the Chronicle apropos of the prosecution of Richard Carlile.