diff --git a/src/Cake.Core/CakeArguments.cs b/src/Cake.Core/CakeArguments.cs
index 1895ec23f4..807b3d4eba 100644
--- a/src/Cake.Core/CakeArguments.cs
+++ b/src/Cake.Core/CakeArguments.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace Cake.Core
@@ -8,7 +9,7 @@ namespace Cake.Core
     /// </summary>
     public sealed class CakeArguments : ICakeArguments
     {
-        private readonly ILookup<string, string> _arguments;
+        private readonly Dictionary<string, List<string>> _arguments;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="CakeArguments"/> class.
@@ -16,7 +17,15 @@ public sealed class CakeArguments : ICakeArguments
         /// <param name="arguments">The arguments.</param>
         public CakeArguments(ILookup<string, string> arguments)
         {
-            _arguments = arguments;
+            _arguments = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
+            foreach (var group in arguments)
+            {
+                _arguments[group.Key] = new List<string>();
+                foreach (var argument in group)
+                {
+                    _arguments[group.Key].Add(argument);
+                }
+            }
         }
 
         /// <summary>
@@ -28,7 +37,7 @@ public CakeArguments(ILookup<string, string> arguments)
         /// </returns>
         public bool HasArgument(string name)
         {
-            return _arguments.Contains(name);
+            return _arguments.ContainsKey(name);
         }
 
         /// <summary>
@@ -38,9 +47,8 @@ public bool HasArgument(string name)
         /// <returns>The argument values.</returns>
         public ICollection<string> GetArguments(string name)
         {
-            return _arguments.Contains(name)
-                ? _arguments[name].ToArray()
-                : null;
+            _arguments.TryGetValue(name, out var arguments);
+            return arguments ?? (ICollection<string>)Array.Empty<string>();
         }
     }
 }
diff --git a/src/Cake/Cake.csproj b/src/Cake/Cake.csproj
index 220b9734ac..3621cc9c1b 100644
--- a/src/Cake/Cake.csproj
+++ b/src/Cake/Cake.csproj
@@ -30,6 +30,6 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Scripting" Version="3.6.0" />
     <PackageReference Include="Autofac" Version="4.9.4" />
-    <PackageReference Include="Spectre.Cli" Version="0.42.0" />
+    <PackageReference Include="Spectre.Cli" Version="0.44.0" />
   </ItemGroup>
 </Project>
\ No newline at end of file