The part of the sentence "just occasionally when" is correct and usable in written English.
You can use it when referring to something that happens only occasionally or rarely. For example, "I only visit the city just occasionally when I have business there."
Why are these cameras unlawful?" Just occasionally, when the authorities get things wrong, someone is brave enough to say sorry.
Poetry, Auden famously declared, makes nothing happen, but one can be almost certain that something happens, just occasionally, when we go to see films.
In the audition Ms. Antoine "would slide her eyes at me just occasionally when she thought I wasn't looking at her.
Just occasionally, when searching for the perfect editor, it's like the other person is reading your thoughts only putting it so much better and more vividly than you could yourself.
Just occasionally, when they're using the music of Bronski Beat or of the Welsh singing solemnly in chorus, the film-makers crank up the emotions in self-conscious and manipulative fashion – and we risk gagging on just a little too much bread of heaven.
The ensemble under Glass stalwart Michael Riesman gives the score verve and drive and just occasionally, when all the visual and musical elements fuse into a unity, as they do in the final scene, the real originality and power of Glass and Wilson's concept comes across.
Just occasionally, as when a white shirt was paired with a mesh skirt or bow was tied at the back waist, there was the meld of sport and elegance that might have energized the show.
Sometimes V.A.T.S can just stop working altogether so be careful and just occasionally check when you hit the V.A.T.S button it works.
Liebrandt's cooking is the culinary equivalent of wordplay — an intellectual exercise cloaked in amusement — and, just occasionally, such as when he dresses up a foie-gras appetizer with a ruby-red skin of hibiscus-beet gelée, like a plum, he succumbs to the superfluous joke.
More than half (61.0 %) did not wear or just occasionally wore masks when they had respiratory infections.
Just do it occasionally when you run into him.
