using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Globalization;

public class Test
{
	public static void Main()
	{
		var strings = new List<string> { "Van Den Broek", "Derksen-van 't schip", "In Het Lid-Van De Boer"};
		var textInfo = new CultureInfo("en-US", false).TextInfo;
    	var pattern = new Regex(@"\b(Van|Den|Der|In|de|het)\b(?:\s+(\w+))?", RegexOptions.Compiled|RegexOptions.IgnoreCase);
        foreach (var s in strings)
        	Console.WriteLine(pattern.Replace(s, m => textInfo.ToTitleCase(m.Groups[1].Value) + 
        	   (m.Groups[2].Success ? $" {m.Groups[2].Value.ToLower()}" : "")));
	}
}