Generic, type safe Configuration Manager

I like to store lots of config data in the Web.Config and I get fed up with having to cast the ConfigSection to the concrete class:

MyConfigSectionHandler handler =
(MyConfigSectionHandler)
WebConfigurationManager.GetSection(sectionName);

So I've written a helper class where now you can use:

MyConfigSectionHandler config =
ConfigManager.Instance.GetSection<MyConfigSectionHandler>
(sectionName);

Here's the code - (I've implemented it as a Singleton for a reason I don't remember now):

public class ConfigManager
{
    private static ConfigManager _instance;
    private static object _lock = typeof(ConfigManager);

    private ConfigManager()
    {

    }

    /// <summary>
    /// Gets a singleton instance.
    /// </summary>
    /// <value>The instance.</value>
    public static ConfigManager Instance
    {
        get
        {
            lock (_lock)
            {
                if (_instance == null)
                {
                    _instance = new ConfigManager();
                }

                return _instance;
            }
        }
    }

    /// <summary>
    /// Gets the section.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="sectionName">Name of the section.</param>
    /// <returns></returns>
    public T GetSection<T>(string sectionName)
where T : class
    {
        return WebConfigurationManager.GetSection(sectionName) as T;
    }
}