I don't think you can really consider it "White flight". The White population is decreasing, but it's not a drastic decrease. You look at the different census tracts and see declines in the White population of around 10-15% in North Lindenhurst and 5-10% in Lindenhurst proper.
By contrast, you see communities in the Philadelphia area that are experiencing true White flight. For instance, check out tract 4028 and 403.104, with declines of 53% and 54% in the White population respectively. And there are a few other tracts in that area that have declines in the White population of 50-60%.
The same thing on the other end of the city. Tract 39 experienced a decline in the White population of 68%, with declines in the 50-60% range for the surrounding tracts. Both of them were plurality White and are now plurality Black.
I'm not necessarily saying that it's good or bad that those tracts are becoming more Black, but I'm just stating a fact that the decline in those areas is enough to be considered "White flight", but that isn't really the case in the Lindenhurst area.
And my trusty source is the following: Mapping the 2010 U.S. Census - NYTimes.com