"on a sudden" is a correct and usable phrase in written English.
It is generally used to indicate suddenness and surprise. For example, “On a sudden, I heard a loud crash outside.”.
With one dish he brought on a sudden whiteout: Atlantic halibut, poached in and sauced with whey, with camomile petals scattered on top and pickled garlic cloves here and there.
Weather lore expert Thomas Willsford, writing in the 17th century, was one of the first people to record this phenomenon: "When on a sudden they do forsake the valleys and low grounds, it foreshows a flood near at hand".
"She took on a sudden look of youth; she looked as if she promised a great future".
But when he talks of Indonesia's embattled president, Abdurrahman Wahid, his voice takes on a sudden fervor.
In the light of his new, albeit minor, fallibility, the rage against time takes on a sudden new pathos.
So BP's spill has prompted scientists to embark on a sudden crash course on the interaction of deep-sea biology with these toxins.
She can switch on a sudden poise for the camera; striking, given that the rest of the time her energy is – as she herself confesses – "kind of manic".
The delicate aroma she exudes, her open smile, her unharnessed breasts bouncing exuberantly in her crisp white blouse as she refills his glass bring on a sudden arousal.
With telecommuting taking on a sudden new attractiveness, the computer industry is benefiting in the short term from fears in East Asia over severe acute respiratory syndrome.
And Hodgson accepts that with Uruguay - who will recall Liverpool's Luis Suarez after his recovery from knee surgery - also having lost their opening game, this match has now taken on a sudden-death element for both teams.
If the teams are still on an equal number of goals after each has taken five shoot-outs, another barrage of five will commence, only this time on a 'sudden death' basis.
