The word 'opportune' often implies something beneficial and is viewed positively. Her arrival was quite opportune, as we needed an extra pair of hands.
Pro Tip 2/3
Sudden Advantage
'Opportune' can express the idea of a sudden, unexpected chance that is advantageous. An opportune discovery led to a breakthrough in the research.
Pro Tip 3/3
Context-Dependent
What's opportune in one situation may not be in another; context determines its suitability. His joke was not particularly funny, but it was opportune and lightened the mood.