WherePrevious.cs

static class MyClass
{
	public static IEnumerable<T> WherePrevious<T>(this IEnumerable<T> source, Func<T, T, bool> predicate)
	{
		if (source == null) throw new ArgumentNullException(nameof(source));
		if (predicate == null) throw new ArgumentNullException(nameof(predicate));

		return 
			source
				.Zip(source.Skip(1), (previous, current) => (previous, current))
				.Where(zip => predicate(zip.previous, zip.current))
				.Select(zip => zip.current);
	}
}